This period of renewed assertiveness came to a calamitous end in 1683 when Grand Vizier Kara Mustafa Pasha led a huge army to attempt a second Ottoman siege of Vienna in the Great Turkish War of 1683–1699. The final assault being fatally delayed, the Ottoman forces were swept away by allied Habsburg, German, and Polish forces spearheaded by the Polish king John III Sobieski at the Battle of Vienna.